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AssigneeMonolithic Power Systems, Inc.
InventorsJohn Robert Shannon, James Copland Moyer, Michael Ren Hsing
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The described DC to AC inverter efficiently controls the amount of electrical power used to drive a cold cathode fluorescent lamp (CCFL). The output is a fairly pure sine wave which is proportional to an input control voltage. The output waveform purity is ensured by driving a symmetrical rectangular waveform into a second-order, low pass filter at the resonant frequency of the filter for all conditions of line voltage and delivered power. Operating stress on the step-up transformer is minimized by placing the load (lamp) directly across the secondary side of the transformer. When configured to regulate delivered power, the secondary side may be fully floated which practically eliminates a thermometer effect on the operation of the lamp. All of the active elements, including the power switches, may be integrated into a monolithic silicon circuit.
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
An apparatus for converting a direct current (DC) signal into an alternating current (AC) signal for driving a cold cathode fluorescent lamp (CCFL), comprising:
A controller for directing a H-bridge network of a plurality of switches to generate an AC signal from a DC signal coupled to the network of the plurality of switches, the AC signal for driving a cold cathode fluorescent lamp (CCFL), the AC signal being generated by a first portion of the network of the plurality of switches periodically opening and closing opposite to the periodic opening and closing of a second portion of the network of the plurality of switches, said first portion of the network being diagonally opposed to said second portion of the network, said H-bridge having a filtering means coupled between the network of the plurality of switches and the CCFL, said filtering means filtering the AC signal delivered to the CCFL, said controller operative to periodically open and close close portions of the network of the plurality of switches generally at a resonant frequency of the filtering means, so that electrical power is provided for driving the CCFL under a range of voltages provided by the DC signal, further comprising a control for dimming the amount of light emitted by the CCFL, the selection of the control causing the AC signal driving the CCFL to be varied in relation to a change in a voltage across a capacitor.
A controller for directing a H-bridge network of a plurality of switches to generate an AC signal from a DC signal coupled to the network of the plurality of switches, the AC signal for driving a cold cathode fluorescent lamp (CCFL), the AC signal being generated by a first portion of the network of the plurality of switches periodically opening and closing opposite to the periodic opening and closing of a second portion of the network of the plurality of switches, said first portion of the network being diagonally opposed to said second portion of the network, said H-bridge having a filtering means coupled between the network of the plurality of switches and the CCFL, said filtering means filtering the AC signal delivered to the CCFL, said controller operative to periodically open and close close portions of the network of the plurality of switches generally at a resonant frequency of the filtering means, so that electrical power is provided for driving the CCFL under a range of voltages provided by the DC signal, wherein the controller implements logical instructions, comprising:
A controller for directing a H-bridge network of a plurality of switches to generate an AC signal from a DC signal coupled to the network of the plurality of switches, the AC signal for driving a cold cathode fluorescent lamp (CCFL), the AC signal being generated by a first portion of the network of the plurality of switches periodically opening and closing opposite to the periodic opening and closing of a second portion of the network of the plurality of switches, said first portion of the network being diagonally opposed to said second portion of the network, said H-bridge having a filtering means coupled between the network of the plurality of switches and the CCFL, said filtering means filtering the AC signal delivered to the CCFL, said controller operative to periodically open and close close portions of the network of the plurality of switches generally at a resonant frequency of the filtering means, so that electrical power is provided for driving the CCFL under a range of voltages provided by the DC signal, wherein the controller implements logical instructions, comprising:
A controller for directing a H-bridge network of a plurality of switches to generate an AC signal from a DC signal coupled to the network of the plurality of switches, the AC signal for driving a cold cathode fluorescent lamp (CCFL), the AC signal being generated by a first portion of the network of the plurality of switches periodically opening and closing opposite to the periodic opening and closing of a second portion of the network of the plurality of switches, said first portion of the network being diagonally opposed to said second portion of the network, said H-bridge having a filtering means coupled between the network of the plurality of switches and the CCFL, said filtering means filtering the AC signal delivered to the CCFL, said controller operative to periodically open and close close portions of the network of the plurality of switches generally at a resonant frequency of the filtering means, so that electrical power is provided for driving the CCFL under a range of voltages provided by the DC signal, wherein the controller implements logical instructions, comprising:
A controller for directing a H-bridge network of a plurality of switches to generate an AC signal from a DC signal coupled to the network of the plurality of switches, the AC signal for driving a cold cathode fluorescent lamp (CCFL), the AC signal being generated by a first portion of the network of the plurality of switches periodically opening and closing opposite to the periodic opening and closing of a second portion of the network of the plurality of switches, said first portion of the network being diagonally opposed to said second portion of the network, said H-bridge having a filtering means coupled between the network of the plurality of switches and the CCFL, said filtering means filtering the AC signal delivered to the CCFL, said controller operative to periodically open and close close portions of the network of the plurality of switches generally at a resonant frequency of the filtering means, so that electrical power is provided for driving the CCFL under a range of voltages provided by the DC signal, wherein said plurality of switches of said H-bridge are MOSFETs and further comprising a gate driver for each MOSFET in the H-bridge network, each gate driver providing amplification of logic signals that control the operation of the associated MOSFET.
A controller for directing a H-bridge network of a plurality of switches to generate an AC signal from a DC signal coupled to the network of the plurality of switches, the AC signal for driving a cold cathode fluorescent lamp (CCFL), the AC signal being generated by a first portion of the network of the plurality of switches periodically opening and closing opposite to the periodic opening and closing of a second portion of the network of the plurality of switches, said first portion of the network being diagonally opposed to said second portion of the network, said H-bridge having a filtering means coupled between the network of the plurality of switches and the CCFL, said filtering means filtering the AC signal delivered to the CCFL, said controller operative to periodically open and close close portions of the network of the plurality of switches generally at a resonant frequency of the filtering means, so that electrical power is provided for driving the CCFL under a range of voltages provided by the DC signal, wherein the periodic opening and closing of portions of the network of the plurality of switches generally at a resonant frequency of the filtering means, further comprising a power phase for the portion of the network of the plurality switches and another power phase for the other portion of the network of the plurality of switches, so that each power phase generates an opposite waveform of the AC signal used to drive the CCFL.
Dependencies are inferred from the claim text.